Saturday, 25 April 2020

Mediterranean diet promotes gut bacteria linked to 'healthy aging'

Eating
a Mediterranean diet for a year boosts the types of gut bacteria linked to
'healthy' ageing, while reducing those associated with harmful inflammation in
older people, indicates a five-country study.

As
ageing is associated with deteriorating bodily functions and increasing
inflammation, both of which herald the onset of frailty, this diet might act on
gut bacteria in such a way as to help curb the advance of physical frailty and
cognitive decline in older age, suggest the researchers.

Previous
research suggests that a poor/restrictive diet, which is common among older people,
particularly those in long term residential care, reduces the range and types
of bacteria (microbiome) found in the gut and helps to speed up the onset of
frailty.

The
researchers therefore wanted to see if a Mediterranean diet might maintain the microbiome
in older people's guts, and promote the retention or even proliferation of
bacteria associated with 'healthy' ageing.

They analysed the
gut microbiome
of 612 people aged 65 to 79, before and after 12 months of either eating their
usual diet (n = 289) or a Mediterranean diet (n = 323), rich in fruits,
vegetables, nuts, legumes, olive oil and fish and low in red meat and saturated
fats, and specially tailored to older people (NU-AGE diet).

The
participants, who were either frail (n=28), on the verge of frailty (n=151), or
not frail (n=433) at the beginning of the study, lived in five different
countries: France, Italy, Netherlands, Poland, and the UK.

Sticking
to the Mediterranean diet for 12 months was associated with beneficial changes
to the gut microbiome. It was associated with stemming the loss of bacterial
diversity; an increase in the types of bacteria previously associated with
several indicators of reduced frailty, such as walking speed and hand grip
strength, and improved brain function, such as memory; and with reduced
production of potentially harmful inflammatory chemicals.

More
detailed analysis revealed that the microbiome changes were associated with an
increase in bacteria known to produce beneficial short chain fatty acids and a
decrease in bacteria involved in producing particular bile acids,
overproduction of which are linked to a heightened risk of bowel cancer,
insulin resistance, fatty liver and cell damage.